Power conversion devices are mounted in railway cars. Power conversion by a power conversion device is performed by a semiconductor that comprises a converter, inverter and the like. The semiconductor generates a large amount of heat due to power conversion. Therefore, typically, a cooling device is attached to a semiconductor that performs power conversion. Patent Literature 1 discloses a cooling device that comprises: coolers that are arranged on the side surface of the semiconductor device and aligned in the advancement direction of the vehicle; and a door for adjusting the amount of travel-generated airflow that is taken in by the coolers.